TAIPEI (Taiwan News) — The Ministry of National Defense reported Friday (April 8) that four Chinese military aircraft had entered Taiwan’s air defense identification zone (ADIZ) during the day.

The aircraft were identified as a Shenyang J-11 fighter jet, a Shaanxi Y-8 EW electronic warfare plane, and in a rare appearance near Taiwan, a CAIC WZ-10 attack helicopter and a Russian-made Mi-17 cargo helicopter.

As on most previous occasions, the aircraft appeared in the southwest sector of Taiwan’s ADIZ and were warned to leave the area. The Ministry of National Defense said it deployed air defense missile systems to monitor the activities of the aircraft.

Friday’s actions marked the seventh day in April that China sent planes into the ADIZ. The intrusions have been widely described as attempts by China to wear down Taiwan’s air defense forces.